548 BEPOET— 1893. 



Daring this period I was engaged on the study of certain points in the 

 anatomy of larvaa of Decapod Crustacea, more especially of Palcemonetes 

 varians. The principal results of the work are published in detail iu two- 

 papers, which have appeared during the course of the year : — 



(1) Preliminary Account of the Nephridia and Body-cavity of 



the Larva of Palcemonetes varians, 'Proc. Roy. Soc.,' 1892, 



(2) Nephridia and Body-cavity of some Decapod Crustacea, 



' Quart. Journ. Micr. Sci.,' xxxiv., 1893. 



The following is an outline of the conclusions arrived at. The green 

 gland commences to develop a lumen about the time of hatching of the 

 larva. The gland then consists of an end-sac and of a short tube which 

 opens externally. The distal portion of this tube subsequently enlarges 

 to form the bladder of the gland, the bladders of the two sides finally 

 uniting in the middle dorsal line, thereby forming the unpaired nephro- 

 peritoneal sac. 



In late embryos and in young larvae a shell-gland is present, consist- 

 ing of an end-sac and tube, and opening at the base of the second 

 maxilla. 



A dorsal sac, completely enclosed by epithelium, is found in both 

 larvae and adults. This sac, which does not contain blood, lies dorsal 

 to the nephro-peritoneal sac, and extends backwards over the front end 

 of the genital glands. The cephalic aorta lies within this sac. 



The dorsal sac is formed as a hollowing out in masses of meso- 

 derm cells, which lie upon either side of the aorta. Two lateral 

 cavities are thus formed, which increase in size and unite below the 

 aorta. From this mode of development it appears probable that the 

 dorsal sac is homologous with the dorsal portions of the mesoblastic 

 somites of Peripatus, and hence must be regarded as a true ccelom. The 

 general body-cavity also seems to be homologous with that of PeripatuSy 

 and to be haemocoelic in nature. 



June 13, 1893. 



111. Eepori on the Occupation of the Table. 

 Notes on How Fish find Food. By Gregg Wilson, M.A., B.Sc, Edin, 



For a month from August 1.5 of last year I occupied the table at the 

 Plymouth Marine Station provided for me by the British Association, 

 and during that time I devoted myself chiefly to the study of the feeding 

 habits of fish. In connection with some work that I had done earlier in 

 the year on the Aberdeenshire coast my attention had been called to the 

 practical importance of Bateson's distinction between sight-feeders and 

 smell-feeders,' and I desired to repeat and test his experiments, and, if 

 possible, extend his results. I find that his main conclusion is a sound 

 one : there are sight-feeders and there are smell-feeders among the fish ; 

 but the distinction is not absolute, and my observations do not in all 

 cases correspond with Bateson's. In a few notes I will summarise my 

 conclusions. 



I. Sight-feeders. — I found no fish that did not use its smelling powers 

 more or less in the search for food. Bateson's instance of the pollack 

 (Gadus pollachiiis), that usually hunts and feeds, relying entirely oil 



> Jown. Marine Biol. Assoc, vol. i. (N.S.), 1889-90, p. 225. 



